Inhibition of ear-emergence time and sensitivity to day-length determined by the group 6 chromosomes of wheat

Increased dosage of the group 6 chromosomes of Chinese Spring wheat delays ear-emergence. Reduced dosage of the same chromosomes has the converse effect and accelerates emergence. Both effects are removed by vernalization. It is proposed that genes on these chromosomes produce a flowering inhibitor, sensitive to vernalization. It is suggested that this inhibitor may be affected by the major Vrn genes for vernalization requirement on the group 5 chromosomes through their production of a flowering promoter which either suppresses the group 6 genes or complexes with the inhibitor, thereby accelerating ear-emergence. A gene (or genes) for sensitivity to day-length was detected on the long-arm of chromosome 6B which, in its absence, delayed ear-emergence under short days. The genes for inhibition of emergence were also probably located on the long-arms of the group 6 chromosomes, but were separate from the gene(s) for day-length sensitivity.